Commit eeeec1d4 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

net: make netdev netlink ops hold netdev_lock() 



In prep for dropping rtnl_lock, start locking netdev->lock in netlink
genl ops. We need to be using netdev->up instead of flags & IFF_UP.

We can remove the RCU lock protection for the NAPI since NAPI list
is protected by netdev->lock already.

Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250115035319.559603-8-kuba@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 413f0271

net/core/dev.c

+2 −1
Original line number Diff line number Diff line
@@ -768,7 +768,8 @@ static struct napi_struct *napi_by_id(unsigned int napi_id) 
}



/* must be called under rcu_read_lock(), as we dont take a reference */

struct napi_struct *netdev_napi_by_id(struct net *net, unsigned int napi_id)

static struct napi_struct *

netdev_napi_by_id(struct net *net, unsigned int napi_id)

{

	struct napi_struct *napi;

net/core/dev.h

+0 −1
Original line number Diff line number Diff line
@@ -23,7 +23,6 @@ struct sd_flow_limit { 


extern int netdev_flow_limit_table_len;



struct napi_struct *netdev_napi_by_id(struct net *net, unsigned int napi_id);

struct napi_struct *

netdev_napi_by_id_lock(struct net *net, unsigned int napi_id);

struct net_device *dev_get_by_napi_id(unsigned int napi_id);

net/core/netdev-genl.c

+25 −21
Original line number Diff line number Diff line
@@ -167,7 +167,7 @@ netdev_nl_napi_fill_one(struct sk_buff *rsp, struct napi_struct *napi, 
	void *hdr;

	pid_t pid;



	if (!(napi->dev->flags & IFF_UP))

	if (!napi->dev->up)

		return 0;



	hdr = genlmsg_iput(rsp, info);
@@ -230,17 +230,16 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info) 
		return -ENOMEM;



	rtnl_lock();

	rcu_read_lock();



	napi = netdev_napi_by_id(genl_info_net(info), napi_id);

	napi = netdev_napi_by_id_lock(genl_info_net(info), napi_id);

	if (napi) {

		err = netdev_nl_napi_fill_one(rsp, napi, info);

		netdev_unlock(napi->dev);

	} else {

		NL_SET_BAD_ATTR(info->extack, info->attrs[NETDEV_A_NAPI_ID]);

		err = -ENOENT;

	}



	rcu_read_unlock();

	rtnl_unlock();



	if (err) {
@@ -266,7 +265,7 @@ netdev_nl_napi_dump_one(struct net_device *netdev, struct sk_buff *rsp, 
	unsigned int prev_id;

	int err = 0;



	if (!(netdev->flags & IFF_UP))

	if (!netdev->up)

		return err;



	prev_id = UINT_MAX;
@@ -303,13 +302,15 @@ int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 


	rtnl_lock();

	if (ifindex) {

		netdev = __dev_get_by_index(net, ifindex);

		if (netdev)

		netdev = netdev_get_by_index_lock(net, ifindex);

		if (netdev) {

			err = netdev_nl_napi_dump_one(netdev, skb, info, ctx);

		else

			netdev_unlock(netdev);

		} else {

			err = -ENODEV;

		}

	} else {

		for_each_netdev_dump(net, netdev, ctx->ifindex) {

		for_each_netdev_lock_scoped(net, netdev, ctx->ifindex) {

			err = netdev_nl_napi_dump_one(netdev, skb, info, ctx);

			if (err < 0)

				break;
@@ -358,17 +359,16 @@ int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info) 
	napi_id = nla_get_u32(info->attrs[NETDEV_A_NAPI_ID]);



	rtnl_lock();

	rcu_read_lock();



	napi = netdev_napi_by_id(genl_info_net(info), napi_id);

	napi = netdev_napi_by_id_lock(genl_info_net(info), napi_id);

	if (napi) {

		err = netdev_nl_napi_set_config(napi, info);

		netdev_unlock(napi->dev);

	} else {

		NL_SET_BAD_ATTR(info->extack, info->attrs[NETDEV_A_NAPI_ID]);

		err = -ENOENT;

	}



	rcu_read_unlock();

	rtnl_unlock();



	return err;
@@ -442,7 +442,7 @@ netdev_nl_queue_fill(struct sk_buff *rsp, struct net_device *netdev, u32 q_idx, 
{

	int err;



	if (!(netdev->flags & IFF_UP))

	if (!netdev->up)

		return -ENOENT;



	err = netdev_nl_queue_validate(netdev, q_idx, q_type);
@@ -474,11 +474,13 @@ int netdev_nl_queue_get_doit(struct sk_buff *skb, struct genl_info *info) 


	rtnl_lock();



	netdev = __dev_get_by_index(genl_info_net(info), ifindex);

	if (netdev)

	netdev = netdev_get_by_index_lock(genl_info_net(info), ifindex);

	if (netdev) {

		err = netdev_nl_queue_fill(rsp, netdev, q_id, q_type, info);

	else

		netdev_unlock(netdev);

	} else {

		err = -ENODEV;

	}



	rtnl_unlock();
@@ -499,7 +501,7 @@ netdev_nl_queue_dump_one(struct net_device *netdev, struct sk_buff *rsp, 
{

	int err = 0;



	if (!(netdev->flags & IFF_UP))

	if (!netdev->up)

		return err;



	for (; ctx->rxq_idx < netdev->real_num_rx_queues; ctx->rxq_idx++) {
@@ -532,13 +534,15 @@ int netdev_nl_queue_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 


	rtnl_lock();

	if (ifindex) {

		netdev = __dev_get_by_index(net, ifindex);

		if (netdev)

		netdev = netdev_get_by_index_lock(net, ifindex);

		if (netdev) {

			err = netdev_nl_queue_dump_one(netdev, skb, info, ctx);

		else

			netdev_unlock(netdev);

		} else {

			err = -ENODEV;

		}

	} else {

		for_each_netdev_dump(net, netdev, ctx->ifindex) {

		for_each_netdev_lock_scoped(net, netdev, ctx->ifindex) {

			err = netdev_nl_queue_dump_one(netdev, skb, info, ctx);

			if (err < 0)

				break;